The present invention relates to a new and improved control arrangement for a textile machine equipped with at least one roll and a ring spindle system, wherein a thread along its path of travel from a creel package to a take-up bobbin placed on the spindle first is wound around the cylindrical surface of the roll in at least one wrap, and subsequently is guided via a thread guide eyelet arranged coaxially with respect to the spindle to the ring spindle system.
In transporting endless filaments or the like, hereinafter referred to as threads, as a rule a substantial portion of a draw roll or a separator or deflecting roll, designated as roll in the following description, is covered. It occurs relatively frequently that following a thread breakage the thread tends to stick to the roll surface due to static friction. If the thread breakage occurs between the roll and the spindle arranged downstream therefrom, the thread which is still taken off from the creel package is wound onto the roll surface, which causes a disturbing lap-up formation thereon, adversely affecting the operation of the equipment. If the thread breakage, on the other hand, occurs upstream of the roll, i.e. between the creel package and the roll it frequently occurs that the "running out" thread tail does not leave the roll surface but is entrained thereby, in such a manner that the thread is wound onto the roll in the reverse direction of movement. Since a ring spindle system is arranged downstream of the roll, from which system the thread can be taken off overhead from the bobbin, also in this case a lap-up is formed on the roll, the formation of which theoretically does not cease until the entire take-up bobbin package placed onto the spindle is unwound.
Control arrangements already are known to the art which aim at eliminating the adverse effects of such lap formations in such a manner that if a thread breakage is detected, the thread supply from the creel package is stopped. Thus, a prior art lap-up control device is disclosed in German Pat. No. 1,940,272, in which the formation of a lap-up on a roll is detected by using a feeler designed as a lever. This lever is placed close to the roll surface and directed towards the roll surface. In this arrangement upon activation of the feeler a cutter arranged upstream from the roll stops the thread supply.
This control device is associated with some considerable disadvantages which render impossible its application on a textile machine equipped with a ring spindle system, such as for instance a draw-twisting machine or a draw-texturing-twisting machine. The control device permits detection of lap-up formations on the roll, independent of whether such are caused by thread originating from the creel package or taken off overhead from the take-up bobbin. However, such control device requires that there already has occurred the formation of a lap-up of a minimal thickness, so that there is always required a cleaning operation for elimination of the lap-up from the roll. Furthermore, this known control device is not capable of effectively counteracting lap-up formations caused by take-off of the thread from the take-up bobbin, since although it can detect the lap-up, it cannot interrupt its continued formation. The lap-up thus increases in size, and there is created a great danger of damage to the working elements of the machine.
According to the German Patent Publication No. 1,535,034 also application of a device for interrupting the thread movement in a textile machine is known to the art, in which device in case of a thread breakage between the drawing arrangement or the supply arrangement, respectively, and the spindle (detected by a feeler contacting the thread between the drawing arrangement or the supply arrangement, respectively, and the spindle), an electric heating element provided in the vicinity of the thread path, for severing the thread, severs the thread from its supply to the drawing arrangement or the supply arrangement, respectively. Also this device shows the disadvantage that the lap-up formations caused by unwinding the thread overhead from the take-up bobbin are not detected and cannot be avoided. The danger of lap-up formation thus still prevails.
Also according to the already known proposal disclosed in Swiss Pat. No. 528,257, in which for detecting a thread breakage, there is accomplished scanning of the rotation of the traveller on the ring using a contact-free traveller feeler, the above-mentiioned danger of thread take-off overhead from the take-up bobbin cannot be eliminated with sufficient reliability, since also in this case the thread can remain threaded in the traveller, so that the traveller continues to rotate on the ring.